Specific features of defect and mass transport in concentrated fcc alloys
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
We report that diffusion and mass transport are basic properties that control materials performance, such as phase stability, solute decomposition and radiation tolerance. While understanding diffusion in dilute alloys is a mature field, concentrated alloys are much less studied. Here, atomic-scale diffusion and mass transport via vacancies and interstitial atoms are compared in fcc Ni, Fe and equiatomic Ni-Fe alloy. High temperature properties were determined using conventional molecular dynamics on the microsecond timescale, whereas the kinetic activation-relaxation (k-ART) approach was applied at low temperatures. The k-ART was also used to calculate transition states in the alloy and defect transport coefficients. The calculations reveal several specific features. For example, vacancy and interstitial defects migrate via different alloy components, diffusion is more sluggish in the alloy and, notably, mass transport in the concentrated alloy cannot be predicted on the basis of diffusion in its pure metal counterparts. Lastly, the percolation threshold for the defect diffusion in the alloy is discussed and it is suggested that this phenomenon depends on the properties and diffusion mechanisms of specific defects.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1260074
- Alternate ID(s):
- OSTI ID: 1323587
- Journal Information:
- Acta Materialia, Vol. 115, Issue C; ISSN 1359-6454
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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